In a photovoltaic power generation module (hereinafter, sometimes referred to simply as a “module”) which transforms solar light energy into electricity, a junction box and a connector for connecting a cable between modules are provided for each module, in order to take out the electricity in a useful form. In the junction box, a by-pass diode or the like are arranged, which is a device for minimizing the influence of reduction in the output of the photovoltaic power generation module caused by a partial shadow cast on the surface of the module or a failure of a battery cell. In this case, since the by-pass diode generates heat, it is required that the whole junction box have heat resistance. As measures for such heat generation, there are proposed methods of increasing the number of diodes, attaching a metal heat-dissipating plate to the by-pass diode for thermal conduction, or enlarging the volume of the junction box to radiate the heat (refer to Patent Literatures 1 and 2).
The junction box, which may also be installed in the outdoors such as on a roof as an attachment of the photovoltaic power generation module, is required to have impact resistance against a flying object and is particularly required to have impact resistance even at low temperatures. In order to improve the impact resistance of the junction box, the wall thickness of the product has been increased, or the box has been enlarged. Similar to the junction box, impact resistance is required also for the connector for a photovoltaic power generation module.    Patent Literature 1: International Publication No. WO 2005/117141    Patent Literature 2: Japanese Utility Model Laid-Open No. 05-001253